HiSET: Math : Multiplication and division

Study concepts, example questions & explanations for HiSET: Math

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Example Questions

Example Question #1 : Multiplication And Division

Multiply, and express the product in scientific notation:

Possible Answers:

Correct answer:

Explanation:

Convert 7,200,000 to scientific notation as follows:

Move the (implied) decimal point until it is immediately after the first nonzero digit (the 7). This required moving the point six units to the left:

It follows that 7,200,000 can be rewritten as .

By similar reasoning, 5,000,000 can be rewritten as .

Thus,

Rearrange and regroup the expressions so that the powers of ten are together:

Multiply the numbers in front. Also, multiply the powers of ten by adding exponents:

In order for the number to be in scientific notation, the number in front must be between 1 and 10. An adjustment must be made by moving the implied decimal point in 36 one unit left. It follows that

Therefore,

,

the correct response.

Example Question #2 : Multiplication And Division

Multiply:

Express the product in scientific notation.

Possible Answers:

None of the other choices gives the correct response.

Correct answer:

Explanation:

Scientific notation refers to a number expressed in the form

,

where and is an integer.

Each factor can be rewritten in scientific notation as follows:

Now, substitute:

Apply the Product of Powers Property:

This is in scientific notation and is the correct choice.

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